Preparation of sulphocarboxylic esters



y i 1&3

arcane rasr'rron or snoo ss'rnas Serial methods for producing salts ofsulpho-carboxylic acid esters of alcohols and, in general, of lipcphilematerials.

The sulphocarboxylic acid esters are surface active or surface modifyingagents and may be employed in the arts for many purposes, based upontheir wetting, penetrating, laundering, detergent, lathering, sudsing,foaming, frothing, emulsifying and similar properties. To make use ofthese properties in the most desirable way, it is very oftenadvantageous and, indeed, necessary to be able to prepare solutions,particularly aqueous solutions, which, at room temperatures or in thecold, contain at least several percent of such substances. In general,the sulphocarboxylic acid esters are prepared and'marketed in the formof salts, usually the alkali metal salts. Such salts are, in general,possessed of relatively low solubility in cold water or in water at roomtemperature and this, therefore, seriously limits the field of utilityof such agents.

I have found a very eflfective method whereby salts of esters-of lowermolecular weight sulphocarboxylic acids with lipophilematerials,particularly higher molecular weight alcohols. which salts possessrelatively poor solubility in cold water or water at room temperature,can be conzeolites, green sand and the like, possess the" capacity foreflecting a cationic replacementlwhen solutions of salts ofsulphocarboxylic acid esters are brought into contact therewith or arepassed through a body thereof. While zeolites and the like have longbeen employed for effecting cationic replacements in connection withsuch inorganic salts as, for example, are encountered in connection withthe softening of water or the like, it is indeed surprising that thisaction should take place in connection with such organic substances asthose with which the present invention concerns itself, particularlysince many-of them-are colloidal or semi-colloidal in character.

It will be seen, therefore, that my invention has its most importantapplicability, although not limited thereto, to the situation where asolution of at least several percent, preferably an rris, Chic,

Application Feb t w (CK. ZGMSE.)

aqueous solution containing from about 10% to 30%, of a salt of asulphocarboxylic acid ester in the cold or at room temperature isdesired and the particular salt at hand is inadequately soluble. I havefound that, at least in most cases, those sulphocarboxylic acid estersalts. which possess relatively low solubility in cold water or water atroom temperature, say to the extent of 0.05%

to 1.0%,, dissolve to a substantial degree in hot I water,'in manyinstances to the extent of 10% to 15% or more. The resulting hotsolution contalning, for example, 10% to 15% of the ester salt is thenpassed into contact preferably with or through. a bed of base exchangematerial containing: replaceable cations of the salt desired. Thisresults in the preparation of a solution containing a substantialpercentage, for example, at

further concentrated. The esters whose treatment in accordance excellentresults are the lower molecular weight sulpho-carboxylicacid esters oflipophile materials such as, for example, lower molecular with the novelprinciples of my invention has given weight sulphocarboxylic acid estersof higher molecular weight alcohols. Substances of 'this class aredisclosed, among other places, in United States Patent Nos. 1,917,250;1,917,255: 2,028,091; in British Patent No. 377,249 and in mycopendingapplication, Serial No. 174,655,111 (1 Novem-' ber 15, 1937, andreference may be ma ethereto. These compounds may be made in variousways as, for example, by reacting a higher molecular weight alcohol suchas lauryl alcohol with chloracetic acidpr chloracetyl chloride and thenreacting the resulting chloracetic acid ester of the alcohol withaqueous alkali sulphite such as potassium sulphite in accordance with.the socalled Strecker reaction. This results in the pro- .duction of alower molecular weightsulpho-carboxylic acid ester of an alcohol, in thespecific instance indicated, lauryl potassium sulpho-acetate having theformula CnHas-O-(f-CHr-SOaK Other methods of preparing thesulpho-carsuch as laui'yl alcohol, with a lower molecular"v weightunsaturated acid such asbutenoic acting the resulting ester with aqueoussodium bisulphite in accordance with the following reactions:

Still other methodsof producing'such agents are disclosed in the patentsand applications referred to hereinabove. V

The following examples will indicate clearly the manner of treating thesulpho-carboxylic acid esters in accordance with the principles of myinvention. It will'be understood, however, that such are merelyillustrative and in no wise limitative of the scope of 'my invention. Itwill be evident that concentrations of materials employed may be variedwithin relatively wide limits, and the same is true of temperatures,times of treatment, and the particular sulphocarboxylic acid esterswhich are utilized in the process.-.

Example I Lauryl potassium sulphoacetate is soluble in water at roomtemperature to the extent of only about 0.1%. To convert it to themagnesium salt which is considerably more soluble, the followingprocedure was carried out.

The base exchange material utilized isthat known as Cristallite which isa fine sand comprising a synthetic aluminum changeable-ion hydratedsilicate theexchange capacity of which, expressed in grains of calciumcarbonate, was 12,000 to 15,000 grains of calcium carbonate per cubicfoot of Cristallite. In 100 cc. of loose Cristallite there were 38 cc.of spaces. The Cristallite was. poured into a perpendicular glass tube,about 34 inches long and having an inside diameter of if; inches, untilthe bed of 'Cristallite was about 17 inches high. The

volume of the bed was 250 cc. The tubing was closed at the lower endwith a one-hole rubber.

400 cc. of cold water and finally with about 400" cc. of tap water at atemperature of approximately 65 degrees C. After substantially all ofthe water had been drained oil, 300 cc. ofa hot aqueous solution(65'de81'ees 0.) containing 13% of lauryl potassium sulphoacetate werepoured on the bed of Cristalli and allowed to stand for fifteen minutes.The solution was then drawn arcane acid-1 (CHs-CH=CHCOOH) and thenreshowed that 67% of the theoretical amount of um salt had beenproduced. I

The times given above are illustrative and it is evident that adiustmentmay be required when the amount of materials treated is extensivelymodified.

Example I! Following the same general procedure as above, I produced themonoethanolamine salt of lauryl sulphoacetate in the following manner:

A 22% monoethano1amine sulphate aqueous solution (400 cc.) was firstutilized to impart monoethanolamine cations to the base exchangematerial, this solution being allowed to pass over the base exchangematerial for about 20 minutes until tests showed that an adequateintroduction gested with boiling concentrated 11,504, the

" 3S0; evaporated oil, and the sulphate ash weighed. The weight of thisash corresponded to 2.8% ofIaury potassium sulphoacetate on the totaldry subs nce, showing susbtantially the complete conversion of thepotassium salt into the monoethanolamine salt. The solution obtainedmade a very valuable base for the produc- 'tion of detergentcompositions such as shampoos or hair washes.

' Example III Pollowing the same general procedure as above.-

I produced the ammonium salt of lauryl sulphaacetate in thefollowing'manner.

A 20% aqueous solution of ammonium sulphatewas initially passed throughthe base exchange material, observing the general conditions describedhereinabove. A hot aqueous solution containing 14% of lauryl potassiumsulphoacetate yielded, when passed through the base exchange material, alimpid solution of lauryl ammonium sulphoacetate having a concentrationof 13.8% solids. ,This solution did not show any solidification orseparation at room temperature, but it froze at a temperature of 0 C.When warmed to room temperature again, however, it

thawed out toform again a clear solution. Anal-- yses showed that thepotassium salt was almost fully converted into the ammonium salt.

.ExamplelV Following the same method, a 15% hot sol tion of monostearinesulphoacetate (potassium salt), at IO-degrees-Q, was passed through abase F exchange material containing triethanolamine cations, previouslyprepared by passing an aqueoussolution containing20% of triethanolaminesulphate through the base exchange material. A clear solution wasobtained comprising mentially the triethanolamine salt of monostearinesulphoacetate, and this solution at room temperature and below remainedclear, showing no evidence ofprecipitation.

of! slowly, the valve being adjusted to extend the-*- flow over aperiodofabout thirty minutes. The solution drawn of! was brilliant,clear and limpid and did not freeze nor show any precipitation at 0degrees C. Analyses showed that the resulting solution contained 13.1%of solids, and a magnesium determination employing standardmethodsExample V In like manner, an alkali metal salt of hexadecylsulpho-propionate was prepared containing 12% of solids, and atatemperature of 80 degrees C. was'passed through a bed of base exchangematerial containing cations introduced aromas therein by passingcommercial triethanolamine' sulphate in the form of a 20% aqueoussolution therethrough. Commercial triethanolamine contains a substantialmixture of diethanolamine and monoethanolamine so that, when treated toform the sulphate, mono-, diand triethaziol- 'amine sulphate werepresent. Accordingly, the

ions of mono-, 'diand triethanolamine were introduced into the baseexchange material, and

the solution of hexadecyl sulph'o-propionate ob-' tained by this methodwas a mixture of mono-, diand triethanolamine salts with a slightamounti'ot unconverted alkali metal'salt. 'I'he final 's'olution waslimpid and clear at room temperature and had detergent and foamingproperties making it suitable for use as a liquid d'etergent.

- Example VI The sulphoacetic acid esters of mixed alcohols obtained bythe catalytic hydrogenation of coconut oil mixed fatty acids wereproduced in the form of the potassium salt thereof, and a hot aqueoussolution was passed through a bed of base exchange material containingions of monodiand triethanolamine. A mixture ofpesters in the form ofmono-, di-, and triethanolamine salts was produced, the solution thereofremaining clear andlimpid at room temperature and considerably belowroom temperature; .Substantially complete conversion to the ethanolaminesalts wasobtained. o

It should be understood that the examples given hereinaboveare merelyillustrative both as to the type of sulphocarboxylic esters treated andthe cations which exchanged in the treatment with the base exchangematerial. The conipounds may be any lower molecular weightsulpliocarboxylic acid esters of substances having 'esterifiable hydroxygroups, asthe descriptive matter identifying'such compounds amply shows.

Furthermore, it will be clear that the sulphocarboxylic acid radical ofsaid esters may contain other groups such as OH, NH2, NR'2,

' .PO3H2, OPO3H2, OR, where R is alkyl, aryl weight lipophile 'ther.While this or cyclo-alml, such as methyl, ethyl, propyl,

cyclo-hexyl, phenyl andthe like.

The sulphocarboxylic acid esters with whose treatment the presentinvention is concerned are, In their preferred form, generallycharacterized by the presence of at least one higher molecular groupcontaining preferably at least eight carbon atoms. usually, although notnecessarily, aliphatic in character, andby the 60 presence 'ofat leastone hydrophile or hydrophillic group in the-form of a lower molecularweight sulphocarboxylic acid radical. Preferably, the lipophile andhydrophile groups are in a state of "balance"whereby-the resultingcompound has theproperty' of reducing thespattering of'margarine; whenused for frying. 1 This concept of "balance" of lipophile andhydrophilegroups is 'treatedin considerable detail in the patent toBenjamin R. Harris, No. 1933 and need-not here be able to predict theexistence of "balance" from merely an inspecthe molecule 01 the com-1,9l7,250,--issuedJul'y' 11 be elaborated 'upon furfbalance'" may bedetermined empirically i-by means or a margarine trying test, asdescribedin said patent, those .in the 5. art will-,in mostcases,'.readily pounds themselves. As a generalrule, the hydro- -phileand lipophile groups should preferably be sium sulphoacetate wherein thelauryl group or,

in other words, the lipophile group, is present at one end of themolecule, and the sulphoacetate or hydrophile' group is present at theother end of the'molecule. However, the invention is by no means solimited and in various instances the hydrophile group or groups may bepresent other than at an extre ity of the molecule as, for ex-.- ample,in such compounds as monopalmitin sulpho-butyrate (sodium salt) dioctylmonoor disulphosuecinate (sodium salt), distearyl monoordi-sulphosuccinate (potassium salt), monopalmitic acid ester or ethylene(or diethylene) glycol sulpho propionate (sodium salt), etc.

It will be understood that the term lipophile group includes groupshaving a definite aifinity for oils and fats and comprises, for example.alkyl, aralkyl, aryl, etheror ester group's containing preferably. atleast eight carbon atoms. The lipophile group possesses predominantly,hydrocarbon characteristics and, in general, is derived fromtriglyceride fats'and oils, waxes, mineral oils, other hydrocarbons, andthe like.

In contra-distinction thereto, the term hydrophile group or hydrophilicgroup includes.

rates, and, in general, any sulpho-carboxylic acid containing less than8 carbon atoms.

Among the sulpho-carboxylic acid ester salts, the treatment of which thepresent invention concerns, and various 'of which have excellentsudsing, foaming, frothin'g, lathering; and detergent powers, are, asindicated, those prepared from higher molecular weight alcohols. Thealcohols from which the sulpho-carboxylic acid esters may bepreparedinclude, among others, the following: aliphatic straight chainand branched chain o 'alcohols such as hexyl alcohol, heptyl alcohol,

Cl, Br, I, F, --OSO2H, QN, SCN, SH, -NC,

octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, laurylalcohol, myristyl alcohol, eetyl alcohol, oleylalcohol, linoleylalcohol, stearyl alcohol, ricinoleyl alcohol, palmitoleyl alcohol,melissyl alcohol, ceryl alcohol, carnaubyl alcohol, myricyl.

alcohol, branched chain octyl, decyl, 'dodecyl,

tetradecyl, hexadecyl and-octadeeyl aliphatic alcohols as; for example,2-ethyl hexanol-l, 2-n butyl octanol-l', 2-butyl tetradecanol-l, and, in

general, the higher molecular weight saturated and unsaturated aliphaticstraight chain and branched chain alcohols. Preferably, the alcoholsenated, such as corn oil, cottonseed. oil, sesame oilyco'coriu't oil,palm-kernel oil, sunflower seed oil, lard, tallow, soya 'bean oil andthe like. those alcohols containing from 12 to 18 carbon atoms beingpreferred. 'Other, alcohols which may be employedare'the cyclo-aliphaticor ali cyclic alcohols'such' as the sterol's, as, for example,cholesterol, iso-cholesterol, .phytoster'ol, .sitosterol,

'hydroaromatic' -alcohols such as abietol, and such unsaturated alcoholsas lirialool, 'citronellol. ge-

of, the foregoing. Also include within the class raniol and the like andhydrogenated products 4 2,106,144 r compounds as the hydroxyand'alpha-hydro higher aliphatic and fatty acids as, for example,ricinoleic acid, alpha-hydroxy stearic acid, al-

. pha-hydroxy lauric acid, di-hydroxy stearic acid,

i-hydroxy-stearic a'cid, alpha-hydroxy palmitic acid, and the like, aswell as esters of hydroxyfatty acids, such as ethyl ricinoleate, castoroil, butylv alpha-hydroxystearate, cetyl hydrorwstearate, and the like.

The term alcohols", as employed herein, is

intended to include alcohols which may or may not contain other groupssuch as carboxyiic,

be produced. As examples of such alcohols may be mentioned, partiallyesterified or partially etherified sugars and sugar alcohols such asmonolauric acid ester of sucrose, monostearic acid ester of dextrose,monopalmitic acid ester of mannitol, dicaproic acid ester of maltose,

mono-octyl ether of sorbitol, monolauryl ether of pentaerythritol,monolauric, acidester of pentaerythritol, and the like; themonoglycerides and diglyceridea'preferably of thefhigher fatty-acids,

as, for example, monolaurin, monomyristin,

monostearin, distearin, diolein, dicaproin, monolauryl ether ofglycerol, di-cetylether of: glycerol,

monostearic acid ester of diethylene glycol, monolauric acid ester ofethyleneglycol, and the like. It is, of course, obvious that thealcohols from which the sulpho-carboxylic acid esters may be producedmay be prepared in accordance with any desired method. For example, manyof these alcohols: may be prepared by the so-called Bouvea'ult and;Blancmethod or, alternatively, by

. the reduction or catalytic reduction with hydro I alcohols may bederived from synthetic processes gen of natural or hydrogenated animalor vege table'fats and oils, 'or mixtures thereof, in ac-.- cordancewith well known practices. I Again the such asby the oxidation ofhydrocarbons or may be prepared by saponiflcation ofwaxes and the like.

tion.

Itis likewise apparent that mixtures .of the foregoing or other alcoholsmay beutilined in the preparation of the sulpho-carhoxylicaeid estersas,..for example, the of alcoholsresulting from the hydrogenation ofcoconutoil or the free,

fatty acids ofcoconut oil. Lauryl alcohol comprises about'45% .of thetotal alcohol mixture, the remaining alcohols running from Co to Cu.Again, mixtures of'alcohols such as are present in the so-called spermoil-alcohols, as well.

as those present in wool-fat, may emcaeiously be Indeed, these higherweight alcohols aref'generallygoifered on' the market in the form ofmixtures of diiierent alcohols.- If

desired for any specific purpose. spcclai'fractlons mina ielni'm f M nrs molecular weight alcohol my be utilised or, if so desiredrthe productsmay be prepared from.

' a single, substantially pure alcohol.

' From the above, it willb'eclear that I am not limited respect-to-the falcohol 0! which my compounds comprise Alternatively, they may beprepared-byv reduction .of aldehydes or by the Grignard reacacid estersexcept that, for most purposes, considering the preferred uses of thecompounds and not the functioning of my process, the alcohols should beof higher molecular weight. A similar situation obtains with respect tothe character of the 'sulpho-carboxylic acid portion of the molecule.

Many of the sulphocarboxylic acid esters are very valuable agents forthe preparation of shampoos, hair washes, and the like in view of their10 excellent sudsing, lathering, foaming and detergent properties.Concentrations of such substances ashigh as, for example, 10 or inaqueous media. produce excellent shampoos orhair washes. Many of thesalts, for-example, the 15 sodium and potassium salts, however, ,are notadequately soluble so that a fully commercially satisfactory and readilyacceptable shampoo product could be made by their use. These alkalimetal salts, however, usuallypcssess. satisfactory solubilitycharacteristics at elevated temperatures 'in that solutions in.hot wateras high as 10% to or more in many cases are readily obtained. By firstproducing the hot-water-soluble salt by the most satisfactory methodscon- 5 sidering sources of raw materials, yields and the like, andforming a solution in hotwater of such salt, I have been able to convertsuch'salt while in hot' solution readily into the modified salt, suchas-a magnesium or triethanolamine. salt or the like which is adequatelysoluble in cold water or water at room temperature.

In certain instances, it may be desirable simply to convert on'e salt ofa sulpho-carboxylic acid ester into a difierent, salt of said esterwithout regard 'to the particular advantages for the obtention. of whichmy invention finds its present greatest importance and practicality. Insuch a case, for example, one may have a particular salt sire to convertit into another salt without regard to whether the desired salt is moreor less soluble' than the salt. at hand. The novel teachings ofinvention may be'employed for such a purof a sulpho-carboxylic acidester at hand and de- 40 However, as previously indicated, the pres-.

t greatest utility of my invention appears to be in converting'salts ofsulpho-carboxylicacid es- ;ters which are normally possessed ofrelatively low solubility in cold water but are quite soluble hancedsolubility in cold water.

The salts of the sulpho-carboxylic acidesters water. In general, saltsofmost inorganicz'and in hot water into agents with substantially en- '50e which may be'produ'ced by my invention are many I and varied, the onlyrequirement being that they be soluble in some measure in either .hot orcold organic may be prepared, Among the inorganic salts arethe alkalimetal and alkaline.

earth salts, such as the sodium, potassium, calcium and m nesium saltsas .weil'as the'salts of q the so-calied heavy Ammonium and substitutedammonium'or organic nitrogenous base salts may also 'eiilca'ciously beprepared, included within'which'class are,;for.=exampl e'. ofv alcohol.amines and alkylolamines as monoethanolam'ine', diethanolamine.'triethanoh amine, propanolamines, 'butanolamlneapentanohamineaglycerolamines, dimethyl monoethanoldiethyl mon, 'dibutylmonoethanolamine diethanoliethyl aminaiw lohml o derivatives of ethylenedismine,

l-amino-2, 3-prolll .ediol, 1.2mm;-

arcane ethylene diamine, diethylene triamine, triethyl? ene tetra-amine,mono-methyl ethylene diamine, monoethyl diethylene tetra-amine,hydrazine and substituted hydrazines, aromatic and heterocyclic basesand cyclic nitrogenous substances such as pyridine, quinaldine,piperi'dine, methylpyridine, and homologues and derivatives thereof,and, in general, primary, secondary and tertiary amines substituted ornot with other radicals such as hydroxy, alkyl, aryl, cyclo-alkyl groupsand the like; quaternary ammonium bases or hydroxides such astetra-methyl ammonium hydroxide, tetraethyl ammonium hydroxide,quaternary.ammonium bases with dissimilar alkyl radicals such as.methyl-triethyl ammoniumhydroxide, propyl-trimethyl ammonium hydroxide,mixtures of any two or more thereof, and the like. It will be understoodthat these organic nitrogenous bases may be employed in pure, impure orcommercial form such as, for example, commercial triethanolamine whichcontains minor proportions of monoand di-ethanolamine. The tabulation ofspecific salts given hereinabove is by nov means meant to be exhaustive,but it afiords to those skilled in the art more than an adequateexemplificatlon of the practice of my'invention.

It will be apparent that I may employ any of the base exchangesubstances, natural or synthetic, inorganic and organic, such as thewell known zeolites, greensands, glauconites, harmotones, certainsynthetic resins, etc. I prefer to employ a base exchange material withgreat exchange capacity and I have foundthat the prodnot referred topreviously and known as "Cristallite is admirably suited for mypurposes.

By the term solution, as employed herein, it will be understood that itis intended to include not only true solutions but also so-calledcolloidal dispersions.

The term higher.', as employed herein, is intended to mean not less thaneight carbon atoms and, concomitantly, the term lower" will beunderstood to mean less than eight carbon atoms, unless otherwisespecifically stated.

What I claim as new and desire to protect by Letters Patent of theUnited States:

1. The method of converting a salt of a lower molecular weightsulpho-carboxylic acid ester of a higher molecular weight'alcohol whichpossesses relatively poor cold-water solubility into a different salt ofsaid ester which possesses substantially enhanced cold-water solubility,which comprises preparing a relatively hot solution containing severalpercent of said first mentioned salt of said ester and then passingthesame into contact with a base exchange material containingreplaceable cations of saidsecond-mentioned salt whereby an exchange ofcations takes place to produce the salt having the enhanced cold-watersolubility. r

2. The method of converting an alkali metal salt of a, lower molecularweight sulpho-carboxylic acid ester of a higher molecular weightalcohol, which salt possesses relatively low coldwater solubility, intoa difierent salt of said ester which possesses substantially enhancedcold-water solubility, which comprises preparing a rela-'.

. 5 salt of the ester has a solubility in water at room temperature ofthe order of notsubstantially in excess of 1%, and the final salt ofsaid ester has a solubility of water at room temperature of at least 5%.

4. The method of converting a salt of a sul-'- phoacetate of a highermolecular weight alcohol, which salt possesses relatively poorcold-watersolubility, into a different salt of said sulphoacetate-which possessessubstantially enhanced cold-water solubility, which comprises preparinga relatively hot aqueous solution containing at least 8% of saidfirst-mentioned salt of said. sulphoacetate and passing the same intocontact with a base exchange material containing replaceable cations ofsaid second-mentio'nedsalt whereby an exchange of cations takes placetoproduce the salt having the enhanced cold- .water solubility. I

5. The method of claim 4 wherein the salt of the sulphoacetate comprisesan alkali metal salt of a s'ulphoacetate of a. higher molecular weightaliphatic alcohol.

6. The method of claim 4 wherein the finally produced salt of thesulphoacetate comprises an organic nitrogenous base salt.

'7. The method of claim 4 wherein theflnally produced salt is an alkylolamine salt.

8. The method of claim 4 wherein the finally produced salt is a salt ofan alkylolamine selected from the group consisting'of mOnoethamolamine,diethanolamine, triethanolamine, and mixtures thereof.

9. The method of converting a salt of a lower molecular weightsulphocarboxylic acid ester of an aliphatic alcohol containing from 12to 18 carbon-atoms which comprises passing an aque-' ous solution ofsaidsalt through a bed of a base exchange material containing cations of asalt to be produced, whereby to cause an ex-. change of cations andproduce a salt different from the salt initially passed through thebedof said base exchange material.

10. In the treatment of a salt of a lower molecular weightsulphocarboxylic acid ester of a higher molecular weight alcohol, thestep of passing an aqueous solution of such salt through a bed of a baseexchange material containing the cations of a salt to be produced,whereby to cause an exchange of cations and produce a salt of said esterdifferent from the salt passed throughthe bed of said base exchangematerial.

11. In the treatment of lower molecular weight sulphocarboxylic acidesters of higher molecular weight alcohols in the form of alkali metalsalts thereof, the method of converting such of said salts which arerelatively sparingly soluble in cold water to salts which are moresoluble in cold water, which includes the step of passing a heatedsolution of said first-mentioned salts through a bed of a base exchangematerial which contains the cation of the said salt which is moresoluble in cold water.

12. In the treatment of salts of lower molecular weightsulpho-carboxylic acid esters of alcohols containing from 12 to 18carbon atoms and which salts are soluble in water at room temperature tothe extent of less than 1%,the-

step of passing a hot solution of such saltfof said ester over a bed ofa base exchange material containing the cations. of a salt to beproduced, whereby to'cause an exchange of cations and produce a salt ofsaid ester which is soluble to the extent of at least 8% in water atroom temperature.

phatic alcohols, the method of converting such of said salts which arerelatively sparingly ble in cold water to suchorganic nitrogen basesalts which are appreciably more sol le .in cold water, which includesthe step of U ng a hot aqueous solution of the alkali metal salt througha bed of a base exchange material which contains the organic nitrogenousbase.

an alkali "metal salt thereof through a bed of base exchange materialcontaining an exchangeable ethanolamine cation whereby to produce anethanolamine salt of said sulphoacetate.

16. In the treatment of a relatively low molecular weightsulphocarboxylic acid ester of a relatively )iigh molecular weight.alcohol, the step of passing a solution of a salt of such ester over abase exchange material to produce a difi'erent salt of said ester.

17. In the treatment of a sulphoacetate of a relatively high molecularweight alcohol, the step of passing a solution of a salt. of such esterover a base exchange material to produce a difterent saltof said ester.

18. In the treatment of a relatively low moarson.

13. In. the treatment or man metal salts or}, sulphoacetates oi.higher/molecular weight all-5 j lecular. weight sulpho-carboxylic acidester of lauryl alcohol, the step of passing a solution of a salt. ofsuch ester througha bed of a base exchange material to produce adiflerent salt of said aster.

19. The method of converting an alkali metal salt of laurylsufphoacetate into another salt thereof which comprises passing asolution of said alkali metal salt of lauryl sulphoacetate through a bedof a base exchange material which contains replaceable cations otherthan those in said solution whereby to recover a solution of anothersalt 0! lauryl sulphoacetate.

20. The method of converting an alkali metal salt of laurylsulphoacetateinto a salt which is soluble at least to the extent of 8% in water atroom temperature, which comprises making a hot aqueous solutioncontaining at least 8%- 01' said alkali salt, and passing said solution,while hot, through a bed of base exchange material containing relaceablecations of a more soluble salt whereby to replace the alkali metal ionwith the cations of the base exchange material and form a solution of asalt of lauryl sulphoacetate which, in the concentration present, willremain clear at room temperature.

.21. The method of converting an alkali metal salt of a suiphoacetate oflauryl alcohol into an allwlolamine salt thereof, which comprisesforming a hot aqueous solution containing several percent of said alkalimetal salt, and passing said solution, while hot, through a bed of baseexchange material containing replaceable alkylolamine ions, whereby toefl'ect an exchange of cations and-obtain an alkylolamine salt which issoluble at least to the extent of several percent in cold aqueous media.

BENJAMIN n. HARRIS.

